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Free Testosterone: High vs. Low Testosterone Levels

With age, we all start losing the vigor and energy we used to have. What if this decline isn’t caused by aging but rather a drop in your free testosterone levels? 

Testosterone deficiency has been detected in 10% – 40% of adult males globally, with age being the most reliable indicator.

This article explores the most common way to discover whether or not you have a free T imbalance and what you can do to remedy the situation.

What Is Free Testosterone?

Testosterone is present in the human body in two forms:

• About 2% of testosterone is free, or bioavailable, and not bound to any proteins in your blood. It is active testosterone.
• Around 98% is bound to either of two proteins known as albumin and sex hormone-binding globulin (SHBG) [2]

Unlike bound testosterone, free T is readily available to act on cells in target tissues. Albumin-bound testosterone has a weak bond and is, therefore, also classified as bioavailable testosterone.

Testosterone is an androgenic hormone produced in both males and females by their respective gonads and adrenal glands. The production of testosterone is controlled by the pituitary gland. 

In males, testosterone acts as the primary sex hormone and is crucial for developing male reproductive organs and protein synthesis necessary for increasing muscle mass. Free testosterone is the active version of testosterone responsible for all these biological processes [1].

What Do Free Testosterone Levels Mean?

Free testosterone level shows the amount of the hormone active in your body. If you have normal T levels, but most of it is bound, you’ll still experience low testosterone symptoms. This is because bound T is practically unavailable to the processes that need it.

The amount of testosterone in your blood is measured in nanograms per deciliter (ng/dL). It can help doctors identify the causes of various conditions such as erectile dysfunction, hair loss, and osteoporosis [3].

What Is the Difference Between Free Testosterone and Total Testosterone?

Free T is not bound to albumin or sex hormone-binding globulin and plays an essential role in muscle growth, sex drive, and mood stability [4]. Your total T levels are the sum of  both bound and free testosterone. 

Testing free T specifically is important, as total testosterone levels may seem normal, but the excessive binding of the hormone may result in a free T deficiency.

Free Testosterone Range

Concentrations outside of the standard free T range for men and women could have varying adverse effects. The most common side-effect is low libido in both sexes. Here is a graphical representation of what your T-levels should be (based on your age and gender)

Normal Free Testosterone Levels in Males and Females

The overall concentration of testosterone in the blood of both males and females decreases with age. 

Free Testosterone Levels by Age [5]

Males

Age Range (in Years)	Free T Level
20 – 30	5.05 – 20.7 ng/Dl
30 – 40	4.65 – 19.0 ng/Dl
40 – 50	4.26 – 17.1 ng/Dl
50 – 60	3.87 – 15.6 ng/Dl
60 – 70	3.47 – 13.9 ng/Dl
70 – 80	3.08 – 12.2 ng/Dl

Females

Age Range (in Years)	Free T Level
20 – 30	0.06 – 1.08 ng/Dl
30 – 40	0.06 – 1.03 ng/Dl
40 – 50	0.06 – 0.98 ng/Dl
50 – 60	0.06 – 0.92 ng/Dl
60 – 70	0.06 – 0.87 ng/Dl
70 – 80	0.06 – 0.82 ng/Dl

Abnormal Testosterone Levels

Low or high testosterone can cause adverse symptoms on both extremes. 

Symptoms of High Testosterone Levels in Men

If T levels exceed the upper limit of the normal range, men may experience: 

• Acne
• Low blood pressure [6]
• Excessive body hair growth

Symptoms of Low Testosterone Levels in Men

Common symptoms:

• Loss of lean muscle mass
• Obesity [7].
• Brain fog, or lack of concentration

Increased risk of developing [8]:

• Coronary artery disease (CAD)
• Metabolic syndrome
• Type 2 diabetes

Partial or complete hypogonadism due to decreased T can cause [9, 10, 11]:

• Erectile dysfunction
• Low sex drive
• Depression
• Low energy levels
• Low sperm count
• Loss of body hair

Male hypogonadism may be caused either by testicular failure or the inability of the pituitary gland to produce follicle-stimulating hormone (FSH) or luteinizing hormone (LH) necessary to signal the production of testosterone in the testes [12].

Symptoms of High Testosterone Levels in Women

• Excessive growth of body hair, especially on the back (hirsutism) [13]

Health conditions like Polycystic Ovary Syndrome (PCOS) causing [14]:

• Infertility
• Acne
• Irregular menstrual cycle

Symptoms of Low Testosterone Levels in Women

Symptoms of low testosterone in women include: 

• Low bone density
• Weight gain
• Muscle weakness [15]
• Chronic fatigue

How To Increase Free Testosterone

There are various products and treatments available within medically sound testosterone therapy:

1. TRT (Testosterone Replacement Therapy)
2. Testosterone Boosters
3. HGH Boosters (Increased HGH is associated with increased T-levels)

Testosterone Replacement Therapy

Aimed at raising T concentration, testosterone therapy is recommended for all men with a testosterone deficiency, with the only exception being men who experience this decrease due to aging.

Treatment methods include: 

• Transdermal: Through an Androderm skin patch applied daily
• Oral patch: Through tablets lodged to the gums, which constantly releases testosterone absorbed through the tissues of the mouth
• Injections: Where testosterone is directly injected and absorbed into the blood
• Gels: Allowing testosterone to be absorbed through the skin

Self-administered supplements include:

HGH Boosters for Men

An increase in the Human Growth Hormone (HGH) concentration directly causes an increase in testosterone secretion [16].

Products that trigger HGH release may help raise your body’s T levels. Read more on our comprehensive review of the best hgh boosters on the market.

T Boosters

These supplements aim to boost both free and total testosterone, increasing lean muscle mass, libido levels, and physical performance abilities. They are typically made from foods associated with increased t-levels. See our Testogen review for how different ingredients affect free T.

Some testosterone boosters have also been reported to increase the risk of developing prostate cancer [17]. That’s why we are very careful to look at the ingredient list of every product we review. See our list of the safest T boosters we found on the market.

How To Decrease Free Testosterone

Doctor-prescribed medication can lower higher than normal levels of testosterone. There is also a good number of foods that kill testosterone. 

Let’s look at both:

Lowering Testosterone In Women

In women, elevated free T levels could cause Polycystic Ovary Syndrome. That’s why high T-levels in women are considered to be more dangerous than the equivalent condition in men. Spironolactone is one of the most effective medications for women with high T.

Spironolactone: How it Works

Although primarily prescribed as a diuretic to treat hypertension, spironolactone acts as an anti-androgen. The drug also increases the concentration of SHBG in the blood, providing a binding substrate to testosterone and effectively reducing the free T concentration [18]. 

Lowering Testosterone In Men

The growing interest around male birth control pills came with good news for men suffering from extremely high testosterone levels. The effects of a pill containing dimethandrolone undecanoate (DMAU) were investigated and found to reduce both testosterone concentration and suppress serum LH production in the study’s subjects [19].

Higher than normal T levels in otherwise healthy men do not cause as many adverse effects as a testosterone deficiency.

Foods That Decrease Testosterone Levels

Some foods can have a significant effect on the body’s testosterone concentration. 

Foods that lower the body’s testosterone includes [20, 21, 22, 23, 24]: 

• Soy [20]
• Spearmint [21]
• Sugar [22]
• Flaxseed
• Trans fats (in processed and fried food) [23]
• Nuts
• Licorice
• Alcohol [24]

FAQ

The information provided regarding testosterone testing, free T levels, and supplements for low testosterone can be overwhelming. The most commonly asked questions about testosterone levels and their answers can be found below.

Conclusion

Imbalanced blood testosterone concentration can lead to various uncomfortable symptoms in both men and women. 

If you suspect you are part of the large percentage of individuals globally struggling with a testosterone deficiency or surplus, free and total T test results may assuage your fears or help you find the cause of the unusual symptoms you have been experiencing.